QLineEdit can't be used for keyboard input after popup menu from another QDialog

My Qt test application consists of 2 dialogs. In both dialogs there are QLineEdit controls.  First, I opened a new dialog by clicking on the button from the main window. On right click on QLineEdit control from the main window popup menu appears, and without closing that menu I clicked on QLineEdit from another dialog, but QLineEdit is not focused. It is not usable, and user can't input anything in QLineEdit until I close that dialog and reopen it.

I have attached source files of the test application.

Thanks in advance.